Beer's civil war heats up with MillerCoors slamming a craft brewer's Keystone Light lawsuit as a 'clever publicity stunt'

Craft beer company Stone Brewing announced Monday it is filing a lawsuit against MillerCoors, alleging that the company has employed copycat marketing of Keystone Light.

MillerCoors responded by calling the announcement a "clever publicity stunt."

Stone Brewing's cofounder accused MillerCoors of "once again playing dirty in their battle against independent beer" — and published a video of himself spitting out Keystone Light.

A craft brewer is slamming MillerCoors in a new lawsuit — and the beer giant is firing shots right back.

On Monday, Stone Brewing announced that it was filing a lawsuit against MillerCoors over the marketing and packaging of its Keystone Light beer.

The craft brewer's co-founder, Greg Koch, said in a video that the light beer brand is trying to "co-op our brand and our good name." Koch accused MillerCoors of deliberately confusing customers by making Keystone packaging look more like Stone brews. He also included a shot of himself trying Keystone Light and spitting it out.

MillerCoors swiftly responded to the allegations, pointing out that Keystone Light's invention predates Stone Brewing by almost a decade.

"This lawsuit is a clever publicity stunt with a multi-camera, tightly-scripted video featuring Stone's founder Greg Koch," MillerCoors representative Marty Maloney said in a statement to Business Insider.

"Since Keystone's debut in 1989," the statement continued, "prior to the founding of Stone Brewing in 1996, our consumers have commonly used 'Stone' to refer to the Keystone brand and we will let the facts speak for themselves in the legal process."

Koch and co-founder Steve Wagner have been vocal critics of Big Beer as Stone Brewing has grown to be one of the top 10 biggest craft brewers in the US over the last two decades.